Magnetic field sensors nowadays typically contain a semiconductor chip and may, moreover, include a magnet which is oriented such that it directs magnetic field lines through a section to be captured of the chip or magnetizes magnetizable elements such as for example elements of a polar wheel. Such magnets are also known as back-bias magnets. Magnetic field sensors having back-bias magnets are used for example as position sensors or rate of rotation sensors but also for other capturing processes of magnetic fields.
One example of a magnetic field sensor contains a chip sensor attached to a system carrier. In some cases, only the chip sensor is supplied to a customer, who positions the chip sensor between a permanent magnet and a movable component such as for example a gear wheel. It is possible that the customer may bend the system carrier in order to position the chip sensor in a preferred orientation. Apart from the preferred orientation, during use it may nevertheless be difficult to realize a desired magnetic field direction, for example a perpendicular magnetic field penetration for a GMR sensor, through the chip sensor. Both of the abovementioned aspects related to the use of conventional magnetic field sensors are undesirable.
Another example of a magnetic field sensor includes a chip sensor package that is positioned relative to a multi-pole magnetic gear wheel. In this case, the gear wheel provides the magnetic field. Such multi-pole magnetic gear wheels are complex and expensive, and the chip sensor package is still subject to the undesirable limitations mentioned above.